EU to Japan ring size converter
Two numeric systems that do not match: an EU size is the inner circumference in mm, while a Japanese size is a JIS number based on inner diameter. An EU 52 is about a Japan 12 and an EU 54 is about a Japan 14. Convert below.
Quick answer
A EU 54 is 14 in Japan (about 54.4 mm inner circumference). Use the converter for your exact size, or the chart below for the full range.
Between two sizes? Size up for a comfortable fit, see how to measure accurately.
EU → Japan at a glance
- 47 = 7
- 49 = 9
- 52 = 11
- 54 = 14
- 57 = 16
- 59 = 19
- 62 = 21
- 65 = 24
EU to Japan ring size chart
| EUEU / ISO | JPJapan | mmCircumference | mmDiameter |
|---|---|---|---|
| 47 | 7 | 46.7 | 14.9 |
| 48 | 8 | 48.0 | 15.3 |
| 49 | 9 | 49.3 | 15.7 |
| 51 | 10 | 50.5 | 16.1 |
| 52 | 11 | 51.8 | 16.5 |
| 53 | 13 | 53.1 | 16.9 |
| 54 | 14 | 54.4 | 17.3 |
| 56 | 15 | 55.6 | 17.7 |
| 57 | 16 | 56.9 | 18.1 |
| 58 | 18 | 58.2 | 18.5 |
| 59 | 19 | 59.5 | 18.9 |
| 61 | 20 | 60.7 | 19.3 |
| 62 | 21 | 62.0 | 19.7 |
| 63 | 22 | 63.3 | 20.1 |
| 65 | 24 | 64.6 | 20.5 |
| 66 | 25 | 65.8 | 21.0 |
| 67 | 26 | 67.1 | 21.4 |
Two numbers that measure different things
This pairing is the easiest to get wrong, because both systems give you a plain number with no letters and no units. It is tempting to assume they are on the same scale. They are not, and they are not even close.
A European size is the distance around the inside of the ring in millimetres, so an EU 54 measures 54 mm around. A Japanese size is built from the distance across the inside instead. An EU 54 ring is about 17.2 mm across, which makes it a Japanese 14. The same ring is a 54 in Paris and a 14 in Tokyo.
Converting through the measurement
Because both scales are measurements, the conversion is exact rather than a lookup. Divide your European number by 3.1416 to get the inner diameter, then multiply by three and subtract 38 to get the Japanese size.
An EU 52 gives a diameter of about 16.6 mm, which works out to a Japanese 12. You never need to guess, but the converter above will save you the arithmetic and will handle the half sizes that fall between.
When you would actually need this
This conversion comes up most often when buying Japanese jewellery from Europe, where a listing quotes only a JIS number, or when a European brand ships to Japan. Japanese sizing is the finer of the two, so a European size will normally map cleanly onto one Japanese number.
Going the other way, several Japanese sizes can share a European number, since European sizes step a full millimetre of circumference at a time. If precision matters, ask the seller for the inner diameter in millimetres and work from that.
Common questions
How do I convert a EU ring size to Japan?
Enter your EU size in the converter above and read the Japan result, or find your row in the chart below. Every value is calculated from the ring’s inner circumference, so it works in both directions.
What is a EU 54 in Japan?
A EU 54 is 14 in Japan. That ring has an inner circumference of about 54.4 mm.
Related conversions
Or see the full ring size chart.